New users not being pushed to MailChimp

[dkellycollins]

I've setup this extension on my firebase instance today, however whenever a new user is created the email is not pushed to MailChimp. Reviewing the function logs I see the line Adding user: [userId] to Mailchimp audience: Infinity followed by Error when adding user to Mailchimp audience Error: Not Found. I've checked the audience id does match the id from MailChimp. Is there a way it needs to be formatted in the configuration?